The invention relates to an apparatus for transforming blanks into corresponding containers of parallelepiped shape, the said blanks being provided with creasings and slits that define the lateral walls, the base flaps and the cover of corresponding containers. Each blank is constituted by two superposed sheets joined one to the other, at two opposite extremities, by two creasings that define the edges of the lateral walls of the corresponding container. Each sheet has, moreover, in the center along an intermediate line, parallel to the aforementioned extremities, a creasing that defines the edge between two lateral walls of the corresponding container.